Lift mechanism



Jan. 6, 1953 F. c. HAuMERsN LIFT MECHANISM 10 SheetsfSheet l ASH FiledMarch 27, 1947 INVENTOR. #dd/we/Ja/y,

BY v

Jan. 6, 1953 F. c. HAUMERSON LIFT MECHANISM l0 Sheets-Sheet 2 FiledMarch 27, 1947 n yM Jan. 6, 1953 F. c. HAUMERSON LIFT MECHANISM l0Sheets-Sheet 3 Filed March 27, 1947 csf; ""'IIIIIIIL so a INVENTOR.

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F. C. HAUMERSON Jan. 6, 1953 LIFT MECHANISM l0 Sheets-Sheet 4 FiledMarch 27. 1947 Jam 6, 1953 F. c. HAUMERSON 2,624,545 y LIFT MECHANISM lOSheets-Sheet 5 Filed March 27, 1947 Jan. 6, 1953 F. c. HAuMER'soN2,624,546

LIFT MECHANISM Filed March 27, 1947 l0 Sheets-Sheet 6 INVENTOR.

Jan. 6, 1953 F. c. HAUMERSON 2,624,546.

LIFT MECHANISM Filed March 27, 1947 l0 Sheets-Sheet 7 Jan. 6, 1953 F. c.HAUMERSON 2,624,546

LIFT MECHANISM Filed March 2v, 1947 y 1o sheets-sheet s `Ian. 6, 1953 F.2. HAUMERSON LIFT MECHANISM Filed March 27, 1947 l0 Sheets-Sheet 9INVENTOR. H1567 (//d uwe/'52.

BY u M Jan. 6, 1953 F. c. HAUMERSON 2,624,546

LIFT MECHANISM Filed March 27, 1947 10 Sheets-Sheet 10 I N VEN TOR. 7,1a7 #dame/*5am /rrra/r/VEKS.

Patented Jan. 6, 1953 UNl'l'ED STATES PATENT OFFICE LIFT MECHANSMApplication March 27, 1947, Serial No. '737,609v

(Cl. 25e-145i) 16 Claims. l

This invention relates to hoisting devices, particularly forautomobiles, trucks and other vehicles, having as its primary object theprovision of an improved cable-operated hoist incorporating a liftingframe or platform of generally rectangular form onto which a vehicle maybe driven and by which it may be lifted while remaining in a horizontalposition, wire rope cable means being provided and arranged to supportthe four corners of the platform.

An important object of the invention is to pro- Vide such an improvedlift structure having four upright posts arranged at the corners of thelifting frame and serving as housings within which the cable means andits operating mechanism are concealed, the mechanism being so designedthat no structural members extend between the corner posts other thanthe lifting frame itself and a single cross-connecting shaft.

Another object is to provide such a four-post cable-type lift whereinthe cable is entirely concealed within the post and the lifting frameand wherein a total of two cables are provided, arranged in such manneras to support all four corners of the lifting frame, as previouslyindicated, yet so disposed that neither the load nor the cable reactionexerts any lateral stress upon the posts, which are loaded entirely invertical compression.

Still another object is to provide a lift mechanism which presents aheater appearance than previously known cable-type four post lifts.

Another important object is to provide improved stabilizing means formaintaining the lifting platform inv horizontal position regardless of`uneven loading of the platform, which stabilizing means also, serves asa. safety device in event of cable breakage.

Another object is to provide a novel structural assembly in which boththe corner posts and the main rails or framework portions of` thelifting platform are ofr rigid box-like construction and function alsoas housing means for the lifting cables, and wherein the corner postsalso serve as housing means for safety devices adapted to prevent theplatform from falling inV event of cable failure,

Still another object is to provide in such a lift structure improved,pan-type drive-on wheel supporting means of simple, reliable and easilyoperable construction, such supporting means being automaticallyadjustable to accommodate vehicles of variant wheelbases.

A further object is to provide in such a lift readily interchangeablemeans whereby vehicles 2 may be lifted either with the wheels resting,in pan-like supports or by so-called free wheeling supports whichsustain the vehicle from beneath and independently of its wheels, sothat the Wheels are rotatable while the vehicle isr ele'- vated.

Other objects and advantages will .be apparent upon consideration of theremaining portion; of the present disclosure.

In the drawings:

Fig. l is a perspective view of` a lift constructed in accordance withthe present invention;

Figs. 2A and 2B are views partly in side elevation and partly invertical sectional elevation, arranged to be read in juxtaposition withFigure 2A at the left, showing the principal components of the front andrear corner posts at one side of the lift structure, andv also showingthe lifting frame portion, parts being broken away and shown in section,and the upper portion of Fig. 2A, which is on a somewhat reduced scale,being taken substantially on the line A--ZA of Fig. 3;

Fig. 3 is a vertical sectional elevational view taken substantially onthe line 3-3of Fig. 1 and locking in the direction of the arrows,showing the upper extremities of the front posts and the hoist andhoist-driving means carriedthereby;

Fig. 3A is a cross4 section taken substantially on the line 3A-3A ofFig. 3` and looking inthe direction of the arrows;

Fig. 3B is an exploded. perspective View of the drag mechanism;

Fig. 4 isa fragmentaryplan view of part of the lifting4 platform and,Wheel pan structure;

5jis a vertical sectional View taken substantially on the line 5 5 ofAFig. 4 and looking'in the direction of the arrows;

Fig. 6 is a sectional detail taken substantially on the line -G of Fig.5 and looking in the; direction-of the arrows;

Fig. 7 is a sectional detail taken substantially on the line 'i-'l ofFig. 6 and looking inthe di'- rection of the arrows;

Fig. 8 is a sectional elevational view corresponding to Fig. 5 butshowing one ofV thestationary wheel supporting pans, and on a somewhatsmaller scale;

Fig. 9 is a horizontal cross-sectional View taken substantially on theline 9-9 of Fig. 2A andlooking in the direction ofthe arrows;

Fig. 10 is a sectional detail taken substantial-ly on the line ID--liilof Fig. 2B and looking in the direction of the, arrows;

Figs. 11 and. 12 are detailed sectionalk views taken substantially onthe lines I i-I I and I2-I2 respectively of Fig. and looking in thedirection of the arrows;

Fig. 13 is a sectional detail of a part of the safety holding mechanismshowing the same in the automatically locked position it assumes inevent of cable failure;

Fig. 14 is a cross section taken substantially on the line I 4--I4 ofFig. 13 and looking in the direction of the arrows;

Fig. 15 is a Ischematic wiring diagram;

Fig. 16 is a view corresponding to a vertical longitudinal sectionthrough the cross tie elements of the lifting frame, showing partly inside elevation and partly in section a modified form of load supportingstructure adapted for the free wheeling support of a vehicle;

Fig. 17 is a plan view of the modied supporting structure, correspondingto a cross section taken as indicated by the line and arrows I'I of Fig.16; e

Fig. 18 is a horizontal sectional plan view corresponding to Fig. 9 butshowing another somewhat modied construction;

Fig. 19 is a vertical cross-sectional view of a part of thelast-mentioned modified construction, corresponding to Fig. 6 but on alarger scale, and

Fig. 20 is a cross-sectional view taken substantially on the line 20-25of Fig. 19 and looklng in the direction of the arrows.

Referring now to the drawings, reference characters I, 2, 3, and 4designate generally the four upright supporting posts for the lift,which posts may be anchored in the floor in the quadrangular arrangementnow regarded as conventional for lifts of this class. Vehicles to beraised are driven or rolled into the rectangular area between the postsfrom one end, as between the posts 2 and 4. The posts are of rectangularcross section, as best shown in Fig. 9, the rectangular sides of theposts being parallel to one another and to the rectangular car-receivingarea. One face of each post is provided with a vertical slot as 6, 1, 8,9, the length of which substantially conforms to the vertical travel ofthe vehicle supporting frame or platform.

The slots 6, 8 are arranged in the rear faces ofthe front posts I, 3,while slots 'I, 9 are formed in the front faces of the rear posts 2, 4,respectively.

The main frame members of the lifting platform comprise longitudinallydisposed side rails I0, I2. The ends of rail I0 are provided withfittings I4, 24, traveling in the opposed slots 6, 1 of posts I and 2while the ends of the opposite side rails I2 are provided with similarttings traveling in the corresponding inwardly facing slots 8, 9 of theposts 3, 4. The side rails Ill-I2 are also of rectangular cross section,as best indicated in Fig. 6, and may, like the posts, be fabricated ofsheet metal. The side rails are somewhat shorter than the space betweenthe front and rear corner posts to accommodate the ttings I4, 24. Frontfitting I4 has a portion I6 slidably projecting into the slot as 6 ofthe adjacent corner post. At the rear end of the rail the somewhatsimilar casting as 24 projects slidably into the adjacent slot as 'I.Formed integrally with the fitting I 4 is a supporting structurecomprising a pair of upright parallel webs I8. Webs I8 are so disposedas to support, in the integral bearing portion I9, a

.sheave 20 so mounted that its groove lies in a vertical planesubstantially centered with respect to both the post and the rail, andthe sheave projects into both the corner post and the rail so that thecable 25 may be trained downwardly through the post, under the sheaveand horizontally through the rail.

The cable 25 is adapted to be drawn upwardly through the post I at will,or paid out and allowed to move downwardly through such post, under thecontrol of winch mechanism mounted upon the top of the post I within ahousing structure generally designated 5. Such winch mechanism willpresently be described in greater detail. The cable passeslongitudinally through the side rail and under a sheave 20 mounted atthe opposite end of the rail in a position corresponding to that of thesheave 26 and likewise projecting into both the rail and the post 2. Thecable is then led up through the post 2 to an anchor bracket 33 near theupper end of the post. The rail I!) is thus slung in the cable in suchmanner that it may be raised and lowered by means of the winch, as willbe apparent, and corresponding synchronously acting means is alsoprovided for raising and lowering the opposite side rail I2, the tworails being rigidly cross connected, as by the tie beams 4I, 52, 43, and44.

Sheave 36 of the rear fitting is journaled in bearing portions 29carried by gusset-like webs 28 integral with tting 24 and projectingupwardly and outwardly from the end of the rail and through the slot 'Iinto the interior of post 2 where they carry safety stop mechanismpresently to be described in greater detail. The anchoring means for theend of cable 25 also includes a rod 4I secured to the end of the cableand forming an upward prolongation thereof, the rod projecting throughan aperture (undesignated) in the horizontally disposed sheet metalbracket portion 33, which is welded or otherwise xedly positioned in thepost near its upper extremity as previously indicated. The upper end ofrod 4I is provided with a cap 42 of inverted cupped form retained uponthe rod as by a nut 43, a helical compression spring 44 being trappedbetween the cup and the bracket 33, and positioned by the cup, toprovide cushioning and takeup means for the cable. A cover |36 concealsthe anchor means and finishes the top of post 2.

The winch housing portion 5 of the front post I forms an upwardlyextending continuation thereof and at its lower end is open into theinterior of such post. Cable 25 extends upwardly into the housingportion 5, where it is wrapped about and secured at its end to the winchdrum 50. The drum is drivable by means of an electric motor M mounted ontop of the winch housing. Driving connection between the motor and thewinch drum includes reduction gearing comprising conventionally arrangedspur gear and pinion sets. Pinion 5I is direct driven by the motorthrough flexible coupling 6I, and drives gear 52 fast with pinion 53 onidler stub shaft 62. Pinion 53 drives gear 54 fast with pinion 55 onidler stub shaft 53. Pinion 55 drives gear 56 fast upon the countershaft64 which also carries Ythe back gear 51 meshing with a gear 58 securedas by screws 65 to the end of the drum 50. The drum is journaled insmooth bearings 66, 63 car- 'ried by housing 5, the last-mentionedbearing engaging a surface portion of the drum between lits helicallygrooved cable-receiving portion and the drum driving gear 58. The webportion II of casing 5 which supports the bearing 68 forms the innerwall of the casing and gear 58 liesdoutsidethe casing -f asA does its;driving; pinion. 5l, these gearsbeingenclosed byfav sheetmetal' coverl'I2 apertured: forrpassage. oifV across. con-f necting shaftt assemblyl5: therethrough directly connected to and drivable by the drumV 5o. An

axial splined extension 'it of the drum bearing portion ill isreceivedinthe splinedVv end'.i portion- 50A receives the, splinedcross-,z shaft., coupling member 85', andthese. parts. arei held againstaxial movement byapin. 18A. Drum 58A, whichis of the same size ast .edrum 5B, accordingly turns synchronously withthedrumv ilto permit thecable A, corresponding to the cable 25 previously described, to be drawnin` andpayed out` With and at the same rate asthe cable 25', so that theside rail i2, similarly suspended in cable 25A, may be lifted andlowered at the same rate, the lifting framew thereby remaining inhorizontal position. Parts associated with the posts 3, Il and thelifting rail I2 corresponding to parts associated with the posts I, 2and lifting rail Iilare designated by, likereference .charactersdistinguished by theaddition of the letterV A to each, andmost of these,parts will be seen to require no separatedescription.

Turning of the drums, gearing and motor shaft in the directioncorresponding to downward movement of the load is opposed by a constantdrag which is sufficient to hold the load suspended except when themotor is energized. The drag mechanism is contained in a supplementalhousing formed by a re-entrant section Si' integral with the gear casecover 9|, and by a cooperating supplemental cover 912 removably securedto the main cover 3 i. The drag housing thus formed is of circularcross-section and. arranged coaxially with respect to the motor shaft.The drag shaft 90 is directly coupled to and forms an axial extension ofshaft portion 68, the later being driven by and co-axial with the motorshaft and carrying pinion 5|.

A friction disk S3 is keyed against rotation in the drag housing but isfree to move axially there'- oi along its supporting key means |22. Thekey means may be cast integrally in the re-entrant drag housing portion9|. Friction disk 93 is frictionally; gripped between apair of disks e?,il urged thereagainstA byv helical compression springs Ille. Springs |53are trapped upon positioning pins l' and between the plate lili and aspring supporting and reaction plate which is mounted rigidly withrespect tothe plate Si. A hub portion integral with plate Si isV formedas a sleeve |U9^upon which the disk itl slides and to the end of whichthe disk |23 is attached as by the screws I. An inner sleeve portioniIfi formed as an integral collar carried by the plate projects into thesleeve |39, and a cooperating inner sleeve portion Ill of the samediameter forms an extension of and' abuts against the end of sleeveportion H3, but is keyed to a hub element I I9 which is in turnl securedto the shaft 95| as by means ofv the pin |2I. Thus, sleeve section I I'iturns as a unit with the hub I I9 while sleeve section ||3 turns as aunit with plates 97, I0 I. The hubl I Isis smaller than thel internaldiameter ofsleeve sections I I3, amiganoyen running clutchspring |23..isinterposedfbetween such sleeve sectionsand the hub I I9 and iswound insuch directionas -to be expanded'against the sleeve sections IIS, Il?when the motor shaft and drag shaft'g areturned in a; directioncorresponding to lowering'of the load; At such time, the` disk portionssl, iI are positively driven through the spring |23 and drag isaccordingly imposed upon1rotation o f the shaft in such direction.Sincethek reactive torque effect of the drag is multiplied by they drivegearing previously described, the impositionl of Y a normal load uponthe platform cannot;turngthel motorv shaft,d andthe load.4 accordinglyremains sus,- pended until themotor is positively energizedk in aYdirection tolowerthe load. Whenthe motor is .rotated inr ai direction toraiseA theload, the

springv clutch assembly overruns and hub; IIS

turnsy freely, so that no additional load is` inrposed upon themotorduring lifting oi"A the load.

In the engaging. faces ofthe dislrsget, B l, IGI, relatively shallowgrooves areA cut, asV indicated at 52. These grooves are substantiallytangential with respect to the centeropenings in thjedisks,`

but the grooves on abutting surfaces extend in opposite directionssothat they cross onevanother at substantial angles at all times. Sincethe abutting grooves can nevel become parallel, there is no tendency onthe part of the outer corner portions of the grooves to strike andinjure one another. Such grooves notV only tend to prevent the trappingof air between the disks, but urge the air outwardly from between thedisks and` insure full efliciency of the friction surfaces at all times.

An additional safety device isprovided inthe form of'a governor adaptedto limit unduly rapid rotation and resultant overly fast dropping of theload, in event of failure of the drag. The governor comprises a pair ofconventionally arranged radially movable fiy weights ISI normally heldin indrawn positioning and free of a cylindrical drumv surface |33formed upon the insidevv of the cover portion SI2. The retractingsprings I3? for the weights are so designed asto limit the speed of theshaft @il and slow the rate of movement of the lift, in the well knownmanner, by braking engagement with the surface |33;

The housing structure 5 isA contoured to support suitable bearing meansfor the gearing, winch drum and the like, includes a tubular supportingportion and serves as a closureA for the upper extremity of post i, aspreviously indicated. Bracket means 955 also carried by the housingserves to support the outer extremities of stub shafts G2, i555v and themotor extension shaft Se. A shroud E@ formed of sheet metal completesenclosure of space between the gear casing and drag housing sections andthe motor M.

The casing 5A mounted at the top of post` 3 is provided with front andrear belled closures 12A, QIA, respectively, and it will be observedthat the arrangement is such that all portions of the operatingmechanism are fully enclosed, with the single exception of thecross-connecting shaft l5.

In order to prevent the load supporting platform :l from tilting towardthe front or rear in event of unequal distribution of the load weightthereupon, stabilizing means is provided within the posts and 3 and soconnected to the front extremities of the side rails |53-, l?. as` toforce such rail extremities to move at half the ratei-of thecountershait the hoisting cable, thereby maintaining a positiverelationship between the position of the cable and the rail ends,corresponding to the positions in which the rails extend horizontally,and the result being to prevent the rails from assuming an angularrelationship with respect to the horizontal. Referring to thestabilizing means contained in post I, it will be noted that a chaindriving sprocket portion IDG is formed integrally with the drum 5U. Achain |2 is engaged with and drivable by the sprocket IUD, one leg ofthe chain extending downwardly to rigid connection with the bracketportion I5. The chain is connected to bracket I5 by a coupling eye-bolt|25. A continuation |04 of the chain, formed of cable, is also connectedto the bracket portion I5 and extends downwardly from the bracket, istrained under a sheave |05 supported near the lower extremity of thepost and then upwardly to connection with the other leg of the chain, towhich it is attached by means of a connector |08. The length of thechain engageable with the sprocket |80 exceeds the vertical travel ofthe lift, so that the looped chain-cable assembly is positively drivenin fixed relationship with respect to the main hoisting cable 25. Theeffective diameter of the sprocket |90 is one-half that of the drum 50,so that the chain-cable assembly |02, ISA! induces movement of thebracket I5 and the connected end of the rail IQ at the same rate as doesthe hoisting cable 25. The stabilizing chain-cable assembly takes somuch of the load as may tend to rock the lifting frame assembly about atransverse axis, transferring such loading directly to the drum sprocketassembly 521-4053.

The stabilizing chain-cable assembly IBZA, IMA and related parts housedin the post 3 correspond to the previously described stabilizingelements contained in post I, and no detailed redescription thereof willbe required.

It will be appreciated that in event of breakage of the main hoistingcable 25, the stabilizing chain-cable assembly prevents the front end ofside rails IIJ, I2 from dropping, transmitting the load through thegearing to the drag. The stabilizing means functions in a similar waywhen the hoist is loaded unequally with the greater proportion of theload nearing the front posts. In event the greater proportion of anunequally distributed load is near the back posts 2, 4, the front endcannot rise due to the xed relationship between the position of the mainhoisting cable and the position of the front end, as determined by thesafety chain-cable assembly, and due also to the fact that such risingwould require the chain to turn the drum in a direction to lift theentire load.

Safety holding means are also provided to prevent the rear ends of therails I0, I2 from dropping in the event of a cable failure. As shown inFigs. 2B, 13 and 14, a screw shaft 40 is rotatably suspended at itsupper end in the bracket 33 and extends downwardly in parallel relationto the cable portion 25 within the post 2. shoulder formed by a washer II rigidly attached as by welding to the upper end 0f the screw shaft 4i)overlies the top of the bracket 33, and the portion of the shaftprojecting upwardly thereabove is provided with means such as thesquared end. ||2 adapted to receive a crank whereby a screw shaft may beturned manually about its longitudinal axis. A guide portion ||5 formedintegrally with the webs 28 carried by the rail end fitting 24 projectsthrough the slot 6 in post 2 and slidably embraces the screw shaft 40,riding freely over the tops of the threads of the shaft as the railsmove up and down. Pivoted between the side webs 28 and located betweenthe cable 25 and shaft 40 is a safety locking dog |20. The dog ismounted upon a transverse pin IIS transxing the Webs 28 and is providedwith a lower extremity having Ventilated threads as indicated at |22conforming, and swingable to and from holding engagement with respect tothe helical threads of the shaft. The toothed portion |22 is normallyurged toward engagement with the shaft by a helical compression spring|24 which urges the upper end of the pivoted dog away from the shaft 4|)and toward the vertical portion of the cable 25, although outwardmovement of the upper portion of the dog far enough to permit thetoothed section I22 to contact the screw shaft is normally prevented byengagement between the roller |25 carried by the upper end of the dogand the cable. In normal operation of the lift, the cable thus ridesfreely over the roller and the portion II5 slides freely along theshaft. In event the cable breaks or lets go, the slacking of the cablepermits the upper end of the dog to move outwardly under the effort ofthe spring |24, and the lower toothed extremity engages the threads ofthe shaft, in the manner shown in Fig. 13. This operation occurs veryquickly in event of cable failure and the load is thus transferred fromthe cable to the shaft so that the rear end of the rail I0 is preventedfrom falling any appreciable distance. Similar safety means, which willrequire no separate description; is of course incorporated in the otherrear pos In order to lower the platform and its load after a cablefailure, the shaft 40 may be turned in the proper direction by means ofa crank (not shown) applied to the upper squared extremity ||2 of theshaft (after removal of the cap or cover |30 which normally finishes theupper extremity of the post 2 and encloses the bracket 33 and the partscarried thereby). The likelihood of both cables 25, 25A breaking at thesame time is of course very remote, and it will be noted that, assuminga failure occurs in cable 25 only, the other side rail l2, which isstill supported by cable 25A, and the front end of the rail I il, whichis then supported by the safety chain-cable assembly |02, |54, may belowered by means of the winch mechanism, which may be so operated as tolower the other three rail extremities intermittently or very slowly,while the screw shaft 40 is turned in such manner as to keep the railends substantially level.

In the arrangement shown in Figs. 1-15, inclusive, the side rails I9, I2carry suspended in a horizontal plane between them the four wheel pansISI, |32, |33, |34. Pans |3I, |33 are adapted to receive and support thefront wheels of a vehicle, while pans |32, |34 support the rear wheelsif, as is usual, the vehicle is driven front first onto the lift.Although the parts are referred to as to positioning in this manner, itwill be observed that the lift functions equally well with the load inthe reverse position. The pans may be formed of relatively heavy sheetmetal, centrally dished or depressed to locate the wheels and providedwith angularly downturned rear extremities (undesignated) adapted toserve as ramps which engage or lie close to the iioor when the liftassembly is in the fully 9 lowered position to permit the vehicle to-move easily into position upon thepans.

The rear wheel pans |32, |34 are fixedlyfpcsitioned with respect to theside rails I9, l2 and with respect to the other components of thelifting frame assembly, being supported bythe cross tie members d, lit,to which they. may beattaehed as by welding. At their ends the cross tiemembers are secured as by means of relatively heavy bolt and nut means|35to outwardly projecting brackets |35 the outer'extremities of whichare upturned and iixedly attached to the respective side rails l0, l2,as indicated-in Fig. 10. As there shown, the outer end of each bracket|36v is provided with a horizontalflange it? rigidly secured as by boltand nut means |38 to a cross plate |133 iixedly mounted as by welding inthe lower portion of the side rail as l2. Bolts |355 extend throughlongitudinal lslots |42 in the supportingbracket |35 sothat theeifective width of the load-supporting platform -as sembly may beadjusted to permit the spacing between the side rails toconform to: anyslight deviations from the normal or intended spacing of the supportingcorner posts. nized that thisis of great convenience duringinstallation, but that no adjustment isrequired at this point afterinstallation.

The front wheel-supporting pans |34, |33 Vare carried by trolley meanssupported by-and'freely movable longitudinally with respect to the siderails IS, I2. The cross-sectional contour of the siderails is as showninY Fig. dlwherein itv is indicated that vthelower extremities of theparallel side web portions itil, |52 are turned inwardly and supportlongitudinally disposed? horizontal plates |54, |55, forming flattracksspaced from one another toA forma slot |55 therebetween.v A plate |55depends throughY the slot to support one end of the cross tiemember asdi'. At each extremity, the plate |55 isv rigidly attached as by Weldingto. a looped sheet-metal frame M56 forming a prolongation thereof andextending horizontally arounda double roller assembly comprisingintegrally .formed roller portionsl |53', itt?, adapted to roll upon thetrackplate sections |54; |55, within the hollow rail. The rollerVportions form'the wheels of the trolley' assembly and are journaleduponanaXial shaft |62 supported-lat its ends in frame portion lSj The top ofthe carriage plate It may be reinforced by means of a cross web as 'M2vwelded' orotherwise rigidly attached thereto. The cross beams si, i2 arerigidly secured at their ends to the carriage plate |55 as by means ofangleV brackets 2% Welded to a plate 2li? bolted to the side of plate|55.

The limits of travel of the 'trolley' assembly are dened by bumperbrackets as 26| Welded to the inner faces of the side rails, faced withrubber or the like as indicated at 2532 and engageable by the ends ofthe roller frame Aportions itt.

Longitudinal movement of the trolleys' and the front pans |31, |33carried thereby is normally prevented by latching means including a pairof dogs as 2li! one of which is engageable with suitable abutment meansas for example the keeper plate 2 l2 secured to the underside ofeachside rail.

The locking dog and the actuating mechanism therefor associated witheach of the front wheel pans are symmetrical and opposite in theirarrangement but otherwise alike, so that detailed description of the oneassociatedV with thepan It will be recog- |33-will suice. Dogs 2 0 movein a vertical plane during swinging' movement and travel in parallelrelation with respect to the rail during travel of the trolley` means.Each dog has an upturned holding portion 2| engageable behind the keeper2 |2, the keeper being so located that the 'holding portion 2 isengageable behind the same when the front double pan assemblyfis movedtothe rearward limit of its travel, the parts when so engagedpreventingl forward movement of's'uch pan assemblies. The dog 2|@ iscarried by a transverse shaft 2 l5 Vjournaled in bracket means i Itattached to therear face of the central web of cross tie member di andextending transversely beneath the pan. A pairof actuatinga-rms 2 i8 arefastened tothe shaft at laterallylspaced points beneath the pan andproject rearwardly in substantially horizontal position. Arms 2 |18 areactuable by a treadlemernber22t of inverted U form, formed ofrelativelyfrigidl strapl metal, the downturned legsy of the U-shapedtreadle being pivotally attached to theI ends of the arms 2li? andprojecting upwardly through slots'- as 222 inthe pan. A transverse'vportion! of theU- shaped treadle extends substantially horizontally ofthe pan and is positioned to be engaged by the wheel of a vehicle on thepanso that-'the weight of the vehicle may release thevhol'dingportion2|! of the dog to permit' the pan assembly to slide forwardly.

When the latching dogs-are engaged with tlfe'rrr keepers the distancebetween theA fron-t and-rear pans does not exceed the wheel base of'Vthe shortest vehicle which the lift is designed to accommodate. When avehicle of 'greater' wheel base is run into the space between the' siderails, the front wheels pass completely over the pans |32, |34- and intothe depressed portions or the pans |3|, |733 before the rear wheelsTeach their centered positions in the pans |32, |34." rIhe front wheelsrelease the treadle bar portions 22D-,y freeing the double front pan andcarriage 'assein bly for forward-movement. Thereafter the front wheelsceaseto rotate-since the front'pan and carriage assembly can moveforwardly more eas# ily than the front wheels of the' vehicle could ru-nupwardly over the treadlebars and off thefr'onts of the Vfront pans, andthe'f-rontpan assembly accordinglyv moves forwardly y until the rearwheels of the Vehicle' roll into 'their proper-positions in the rearpans. The vehicleis"tl-ien'y of course stopped with all four wheelsproperlyrest'-A ing in ltheir respective supporting pans andthe hoistmay be operated to raiseV and lower the ve` hicle as desired. Afterlowering of the vehicle, when it is to be removedfrom' `the lift, 'itisr'moved rearwardly, normally under its own'v power. The rearlwheels(which are. normally the driving wheels) pass oil the rear pans in thebacking of the vehicle, While 'the front wheelsremai'n'in the frontpans, due 'to the depressionsin' the latter, pulling the front panassembly 'to the rear until it reaches'the latched position. Thereafter,rearward movement of the front panassembly bei-ng arrested, the frontwheels-roll from'the' front pan assembly andV the vehicle` may' 'bebacked clear. It will be understood'that inr event the hoist is to beused with a vehicle which is driven by its front wheels, it is merelynecessary to run the vehicle backwardly onto the lift instead of frontend iirst, and identical operation, and automatic adjustment ofthespacing ofithe wheel pans to the wheel base of the vehicle will occur.The dogs are urged toward the latched position by a torsion springwrapped around'the 1 1 .shaft 2|5 and reacting against the dog andlagainst one of the brackets 2 I6, as shown in Fig. 5, such spring alsoserving to return the treadle 220 to the elevated position, as will beapparent. When it is desired to elevate the vehicle with the wheels freeof the pans, supplemental supports are provided constructed as shown inFigs. 16 and 17. Three or four such supplemental supports are used, eachconsisting of a beam of U section and of such length as to bridge and torest on the tops of the cross rails 4|, 42 or, alternatively, the rearcross ties 43, 44, the spacing between each pair of ties being the same.Description of one of the beams in detail will suffice. The beam isgenerally designated 225 and is provided with a dropped horizontalcentral section 226 which carries centrally disposed therein arelatively massive nut assembly 228 in which a jackscrew 230 isthreadably engaged in vertical position. The jackscrew carries at itstop a lifting head 232 with respect to which the screw may beindependently rotatable, thrust bearing means as 233 being interposed.The screw is rotatable about its axis to raise and lower the lift# inghead through the agency of ratchet-type actuating means including thehandle 235, pawl means 236 carried thereby and a ratchet wheel 238 xedlysecured to the lower end of the jackscrew and engageable by the pawl inthe usual manner. The pawl is double ended and is reversible inposition, to change the direction in which the screw is rotatable by thehandle, through the agency of the pivot pin 248 for the pawl, the pawlbeing fast upon the pin 248 and the pin projected downwardly to permitthe pawl to be rocked so as to engage the ratchet teeth in eitherdirection, as will be apparent. Two such jack-type supplemental supportsare arranged between the front pans |3|, |33, each extendinglongitudinally to bridge the rails 4|, 42, and it will be appreciatedthat they may be moved laterally to properly engage beneath the vehicleaxle or the lifting pads or other portions with which independent wheelsuspensions are commonly provided for the reception of lifting jacks.

A second pair of such supplemental jack-type supports may be similarlyarranged between the pans |32, |34 bridging the cross ties 43, 44 toengage the other axle or suspension system of the vehicle, oralternatively, one such jack may be positioned midway between the pans.In use, the vehicle is run into place upon the pans, and the hoist israised in the manner previously described, with the pans supporting thevehicle by its wheels in the same manner. When the hoist has been raisedto a convenient height to permit a man to work beneath the same, he mayplace the jacks in position and then manipulate the several jack handles235 to raise the vehicle until the wheels are free of the pans. Uponcompletion of the work, the vehicle is again lowered onto the pans bymeans of the jacks, and the jacks are removed before the lift islowered, so that upon reaching the ground level the vehicle may bebacked or run from the lift without interference by the jacks.

While the present invention is not particularly concerned with the modeof control of the motor M, a suitable control system is indicatedschematically in Fig. 15. As there shown, the motor is of the reversibletype, equipped with two eld windings 24|, 242, the connections of whichwith respect to the supply lines L may be reversed by reversing switchmeans of the six-pole doublethrow type, actuable by means of a rockablehandle 239. When the contact blades 243, 264, 268 of the switch are inthe upper position, shown in full lines in Fig. 15, a circuit iscompleted from supply line L-l through switch blade 243 and switchcontacts 244, 245 which are then connected by such blade to the fieldcoil 242 of the motor by way of a conductor 260, connected to one of thelower contacts 252, the last-mentioned contact being permanentlyconnnected to upper contact 245 by a lead 26|. A return connection fromfield coil 242 is provided by a conductor 262 connected to lower contact25 I, which is permanently connected to upper contact 246, as indicatedat 263. Switch blade 264 then completes a circuit between contacts 246,241, the last-mentioned contact being connected to field coil 24| by aconductor 265, return connection from the field coil 24| to supplyconductor L-2 being provided by a conductor 266 connected to upperswitch contact 248, which is then connected to switch contact 249 byswitch blade 268. Contact 249 is connected to the line L-2 by aconductor 218, connection between switch contact 244 and supplyconductor L| being provided by a conductor 212. When the field coils areconnected in the indicated manner through the feed lines 218, 212 themotor may rotate in a direction to raise the hoist. A limit switch,generally designated 215, is arranged to open the circuit through thelines 210, 212 when the hoist reaches the desired upper limit of itstravel. The switch is actuable through the agency of an arm 211projecting into the path of the bracket portion I5 and adapted to beraised by the latter to break the circuit.

When the switch is thrown to the reverse position indicated in dottedlines in Fig. 15, in which the switch blades bridge the lower series ofcontacts, it will be seen that a reverse series connection isestablished through the field coils 24|, 242, supply line L| being thenconnected to coil 24| by way of conductor 288, contact 255, blade 268,contact 254, permanent connector 283, contact 248 and conductor 266.From coil 24| a connection is established to coil 242 through conductor265, contact 241, permanent connector 284, contact 253, blade 264,contact 252 and Wire 260, a return connection from coil 242 to thesupply line L-2 being provided by conductor 262, switch blade 243,contact 250 and conductor 282. This connection may rotate the motor in adirection to lower the hoist. A limit switch 285 is preferably providedfor opening the lines 280, 282 to arrest rotation of the motor and stopthe hoist when the lifting frame reaches the desired lower limit of itstravel. Switch 285 is actuable by an arm 281 which also projects into aposition to be engaged by the bracket portion I5, as indcated in Fig.2A.

The switch is constantly urged to an intermediate position in which allof its contact blades 243, 264, 268, are out of contact with all of thecontacts previously mentioned, a spring 288 of the helical tension typebeing connected to an arm 298 projecting laterally from the switch bladesupporting shaft 295 and anchored at its other end to a xed support 292to turn the switch blades to the intermediate position in which themotor is ole-energized when the switchactuating handle 239 is released.It is thus necessary for an operator to be present and to positivelymaintain the switch in one of the two positions shown in Fig. l5 inorder to operate the hoist, while in event of any failure of themechanism the hoist is immediately stopped upon 1 depends through theslot 556.

Vshown in Figs. 19 and 20.

lasagne release ofthe handle-'139 andf the-safety-'mecha- -nismpreviously descr-ibedisautomatically activated ifnecessary.

YIn-Figs. 18, 19, and 20, 'an alternative supporting structure :for themovable front pan assembly is shown. yAs there indicated the inturnedbot- -rail for a short distance, thereby providing a pair-ofspacedupwardly opening channel portions generally designated 45A, 1355,within the "rail, the bottoms of which channels maybe rounded to partlycylindrical contour. Between channels'45ri,-455, whichserve as tracks, alongitudinal slot 56 is formed through which the supporting portion ofthe'trolle'y means may ldepend Vto carry the supporting structure forthe front wheel pans.

Eachtrolley means consists of ra pair of Wheels'fi't, it adaptedto-travel in vertical positions in the channel track portions 354,

V455 respectively and connected and positioned by a supporting axle M2extending transversely within the channel'3l2 above the level of theupstanding re-entrant web portion 653. The axle is journaled in abushing 'lll-3d which extends substantially the full distance betweenthe trolley wheels'l, '456, and a longitudinally arranged plate 465 issuspended 'from the collar 454 and The plate ris provided at its forwardextremity with an enlarged opening 5532 substantially exceeding thediameter of the collardfi. The Vapertured portions of the plate hangupon the bushing, as best The rear extremity of the trolley frame plate455 is supported by a similar trolley wheel assembly including a pair ofsupporting Wheels i368, ll also adapted to ride in the internal channels54, c55. the other portions of the rear trolley wheel assembly will beseen to correspond to'those at the `front and to require noredescription.

The extremities of the supporting cross ties as 34! for the front Wheelpans as 43| are supported in openings 595 in the depending portions ofthe trolley plate A65. The ends of the tie members are cut away, asindicated in Fig. 19, and provided with downturned ends as indicated at5036 adapted to depend outside the plate portion by which they are heldto prevent accidental displacement of the cross ties. Reinforcing platesas 53 may also be Welded to the sides of the cut-'away portions of theties to reinforce their supporting extremities. It will be appreciatedthat the plate @.55 may tilt with respect to the supporting bushingsdtd, and may also move laterally over such collars to the extentpermitted by the slot portion litt, thereby permitting the parts toposition themselves properly and work freely without'regard to anydisalignment or distortion of the supporting corner` posts or otherparts.

Analogous vmeans for llocking the rolling carriage assemblies in theirrearmost positioning until released by the wheel of a vehicle maybeprovided, including locking dogs as 2li) engageable with keeper means 2I 2 and actuable through trip means analogous with that alreadydescribed.

It will be noted that if a load sufficient to flex the' cross tiemembers Lil, 42 is imposed upon the lift structurerstA above described,it results in a tendency to rock the trolley assemblies and tilt therails IS, I2 inwardlyat their tops, due` to"l the rigid connections'between' the cross ties 1.

These and f `and trolley means. This is equivalent tota tendency torockthe rail I2` clockwise, as viewed in Fig. 6. This tendency is offset bylaterally displacing the point of connection of the stabilizerchain-cable assembly with respect to the longitudinal vertical centralplane of the side rail, While the sheave' and accordingly the plane ofsuspension of the rail is centered with respect thereto. As best shownin Fig. 9, the coupling means m5 for the stabilizing chain W2 isconnected to the bracket I5 nearer the outside 'of the -rail structure.This will be seen to result in a rocking couple tending to twist therail I2 counterclockwise, as viewed in Fig. 6,A and offsetthe-counter-rotating effect of the load.

In the embodiment of Figs. 18, 19, andv 20,y the stabilizing chainconnecting means as 1l5`may be centered with respect to the bracket SI5and the side rail, since any distortion of the cross ties under loadinghas no material eiTect except Vto slightly tilt the freely hangingplates t, im-

`shortening and lengthening the sling portion to raise `and lower thebight portion and the frame carried thereby, including winch means fortaking up and paying out the cable constituting one of the legs of thesling, and stabilizing means including -a portion drivable with saidwinch and at a fixed speed ratio with respect thereto and having areversible drive connection with said winch means whereby the winchmeans is also drivable by the stabilizing means, said stabilizing meansbeing connected to an end portion of said frame to maintain the same ina desired position with respect to the cable `and prevent unwantedtilting 0f said frame.

2. Means as set forth in claim 1 in which the upper end of one leg ofthe cable sling is anchored within one of said posts, winch meanscarried by the other posts of the pair near its top and engaging theupper extremity of the other leg or" the loop and operable to reel inand pay out the same to raise and lower the bight portion and thelifting frame carried thereby.

3. Means -as set forth in claim 1 in which the upper end of one leg ofthe cable sling is anchored Within one of said posts, winch meanscarried by the other posts of the pair near its top and engagingtheupper extremity of the other leg of the loop and operable to reel inand pay out the same to raise `and lower the bight portion and thelifting frame carried thereby, said stabilizing means comprising alooped flexible but substantially inelastic driving member also housedwithin said posts which carries the winch means and having a reversibledriving connection with said winch means and engaging a portion of saidframe structure to force all portions of said frame structure and thewinch t0 move at a predetermined relative rate corresponding to the ratetially -horizontal `Aduring verticalntravel thereof.

4. In a four-post vehicle lift construction including a pair oflaterally spaced substantially parallel vertically movable side railportions extending lengthwise of vehicle carried by the lift, hoistmeans connected to both ends of each of said side rail portions andactuable to raise and lower the same, crosstie means rigidly connectingsaid side rail portions intermediate the ends thereof and formingtherewith a load-supporting platform, and means for offsetting torquetending to turn said side rail portions about longitudinal axes as aresult of bowing of said crosstie members under load, comprisingstabilizing means connected to one end of each of said side railportions and laterally offset in such direction from the line ofsuspension of the side rail portion, which line of suspension is definedby the points of connection of said hoist means to said rail ends,whereby the reaction imposed upon the side rail portions by thestabilizing means tends to a counteract the moment resulting from suchbowing of the crosstie members.

5. A four-post lift structure comprising four upright hollow postslocated at and dening the corners of a cuadrangular lift area, a siderail extending between two of the posts representing a pair thereoflocated upon one side of the lift area and a corresponding railextending between the other pair of said posts upon the opposite side ofsaid lift area, said rails being carried by the posts and being ofhollow construction and each having a longitudinal slot extending alongits bottom, vehicle-supporting means including a longitudinally movablecrosstie member extending transversely between said rails, a carriagemovable "f within each of said rails, and means projecting downwardlyfrom each carriage through the slot in the rail and supporting saidcrosstie member.

6. Means as set forth in claim in which said supporting means connectedto and extending downwardly from the carriage upon at least one side ofthe assembly is laterally shiftable with relation to the rail.

'7. Means as set forth in claim 5 in which said supporting meansconnected to and extending downwardly from the carriage upon at leastone side of the assembly is laterally shiftable and rockable withrelation to its carriage.

8. Means as set forth in claim 5 in which said supporting meansconnected to and extending downwardly from the carri-age upon at leastone side of the assembly is laterally shiftable and rockable withrelation to the rail.

9. Means as set forth in claim 5 including cable-type lifting meanssupported by said posts and connected to said side rails to raise andlower the same and including cable portions extending longitudinallythrough said rails.

10. Means as set forth in claim 5 including cable-type lifting meanssupported by said posts and connected to said side rails to raise andlower the same and including cable portions extending longitudinallythrough said rails above the carriage.

11. Means as set forth in claim 5 including a sling-type cable liftingmeans for each of said side rails comprising vertical cable legsarranged in the posts and a substantially horizontal bight portionextending through and movable longitudinally of each rail above thecarriage therein.

12. A four-post lift structure comprising four hollow upright postsarranged at and defining the corners of a generally quadrangular liftarea, a pair of side rails, one extending longitudinally between the twoposts representing a pair of such posts located upon one side of saidarea and the other similarly extending between the posts representingthe opposite pair, a platform-forming crosstie extending between saidrails, support devices for the cross-tie movable on the rails, hangerstraps rockably mounted on the devices, opposite ends of the cross-tiebeing supported on the straps, and means carried by said posts forraising and lowering said rails simultaneously.

13. In a lift construction of the four-post type, a pair oflongitudinally disposed substantially parallel side rails, a pair ofcrosstie members connecting said rails near one end and arrangedparallel to one another, a second pair of crosstie members connectingsaid rails near the opposite end and also disposed parallel to oneanother, means carried by said crosstes and adapted to form rests forthe wheels of a vehicle to be lifted, and supplemental freewheeling-typelifting means for raising the vehicle with respect to said crossties andwith respect to said first-mentioned supporting means, said supplementallifting means comprising beams bridging the crossties of each of saidpairs of crossties, and vehicle jacking means carried by said beams.

14. In a four-post lift construction comprising four upright hollowposts arranged at the corners of a quadrangular lift area, a liftingframe structure having portions vertically movable with respect to theposts and lying close to the same, sling-type cabie lifting means housedat least partly within said posts and extending beneath portions of theframe structure in the form of a generally U-shaped loop, driving meansfor lengthening and shortening the loop to raise and lower the framestructure, and stabilizing means also arranged within at least one ofsaid posts for preventing unwanted tilting of the frame structure withrespect to the posts, said driving means including winch mechanism, saidstabilizing means including supplemental reversible driving meansoperatively interconnecting the frame structure and the winch mechanism.

l5. l'n a four-post lift construction comprising four upright hollowposts arranged at the corners of a quadrangular lift area, a liftingframe structure having portions vertically movable with respect to theposts and lying close to the same, sling-type cable lifting means housedat lea-st partly within said posts and extending beneath portions of theframe structure in the form of a generally U-shaped loop, driving meansfor lengthening and shortening the loop to raise and lower the framestructure, and stabilizing means also arranged within at least one ofsaid posts for preventing unwanted tilting of the frame structure withrespect to the posts, said driving means including a windlass, saidstabilizing means comprising a supplemental looped driving member havinga two-directional driving connection with the windlass and with theframe structure.

16. In a four-post lift construction comprising four upright hollowposts arranged at the corners of a quadrangular lift area, a. liftingframe structure having portions vertically movable With respect to theposts and lying close to the same, sling-type cable lifting means housedat least partly within said posts and extending beneath portions of theframe structure in the form of a generally U-shaped loop, driving meansfor lengthening and shortening the loop to raise and lower the framestructure, and stabilizing means also arranged within at least one ofsaid posts for preventing unwanted tilting of the frame 17 structurewith respect to the posts, said driving means including a windlassappurtenant to one reversible driving connection with the windlass andwith the frame structure and housedi in j said last-mentioned post andcomprising a vertica-ily elongated loop of flexible but substantially ,j

inelastic character connected at one point to said fd frame structure.

FRED C. HAUMERSON.

REFERENCES CITED The following references are of record inthe file ofthis patent:

Number 18 UNITED STATES PATENTS Name f Date Walker May 8, 1934 Hott Mar.5, 1935 Brie June 23, 1936 Babel July 21, 1936 Martin Dec. 6, 1938 KrollMay 7, 1940 Steedman Apr. 15, 1941 FOREIGN PATENTS Country Date GreatBritain Dee. 11, 1930 Great Britain May 12, 1932 Great Britain Jan. 16,1936

